PROJECT ABSTRACT/SUMMARY Adolescent girls and young women between the ages of 15 and 24 bear a disproportionate burden of negative sexual and reproductive health (SRH) outcomes worldwide. This is particularly so in Sub-Saharan Africa (SSA), where the leading causes of death among girls aged 15-19 are complications related to pregnancy and childbirth. About a third of all new HIV infections in SSA also occur in young women aged 15-24 annually. Research from various high-income countries (HICs) suggests that vulnerability to negative SRH outcomes, including early pregnancy and childbirth and sexually transmitted infections (STIs), may be elevated in girls and young women who reach menarche at an early age (an indication of early sexual maturation). There are indications that this also applies to girls in SSA, but the little available evidence is inconclusive. The few menarcheal data from SSA also suggest secular trends of declining age of menarche across SSA. There is an urgent need to better understand the effect of early menarche on SRH in SSA, and the underlying process by which early menarche affects SRH given the high burden of negative SRH outcomes experienced by SSA girls and young women. Using data from ?Gendered Social Context of Adolescent HIV Risk Behavior in Ghana? (R01HD06101; PI: Bingenheimer, PhD), a three-year longitudinal study of adolescents from two peri-urban communities in Ghana, the current proposal aims to begin to address this gap in knowledge. The longitudinal nature of the data being used in the proposed study will allow me to examine girls? transitions to various outcomes over time relative to their age at menarche thus facilitating causal inferences ? an advantage over the few other available studies from SSA that have all used cross-sectional data. The current proposal will examine how early menarche affects various SRH outcomes in adolescent girls and young women in SSA to determine whether patterns seen in HICs also apply to SSA or whether unique patterns are found in SSA. Building on the methodological skills and substantive knowledge I gain through my training activities, I will explore the process by which early menarche contributes to negative SRH outcomes in SSA with the following specific aims: 1) to test whether early menarche is associated with sexual violence, risky sexual behavior and early pregnancy in Ghanaian adolescent girls and young women; 2) to explore the process through which early menarche leads to negative SRH outcomes among girls in SSA by assessing the meditational role of forced first sex, early sexual initiation and early marriage; and 3) to identify which factors that are known to protect against or increase vulnerability to negative SRH outcomes, including education and alcohol use, interact with early age at menarche to affect SRH outcomes in SSA. The research project will contribute to a greater understanding of the SRH consequences of early menarche in SSA youth and help identify factors to intervene on to mitigate negative SRH outcomes resulting from early menarche. The project will provide training and research experiences necessary for my development as an independent researcher.